It is well known that the bodies moving through the gaseous or other environment decelerate themselves, so the speed or their motion decreases. This concerns the bodies of the Solar System as well. Meteoric bodies, entering the upper layers of the Earth atmosphere, slow down their movement. Artificial satellites with low orbits are also subject to deceleration. At that, it was discovered that the satellites, slowing down their motion, approach the Earth; however, strange as it is at first sight, their speed increase in the course of their deceleration. Besides, it was discovered that the orbits of artificial satellites, subject to braking in uppermost layers of the Earth atmosphere, not only approach the Earth, but also become less elongated; in other words, their eccentricity decrease.

Based on the aforesaid, one could draw the conclusion that all the celestial bodies of the Solar System, as well as other star-planet systems, are subject to deceleration during galactic winters, when the Solar System passes through the spiral branches, or through the plane of Galaxy between these branches, or through gas-dust clouds at the periphery of the Galaxy. At that, the deceleration is proportional to the density of diffuse matter and to the speed of the Solar System with regard to gas-dust environment. Moreover, the longer is the galactic winter, the more significant is the deceleration of the Sun in its circulation around the galactic centre; of the planets, asteroids, comets and meteoric bodies in their circulation around the Sun; and of the satellites in their circulation around planets.

In the course of deceleration by gas-dust environment, the planets and other celestial bodies of the Solar System will gradually approach the Sun, the satellites will come closer to their planets, while all the Solar System will approach little by little to the centre of the Galaxy. Of course, the same concerns all the celestial bodies of our Galaxy, as well as of all the other galaxies.

The speed of approach of a celestial body to the central body of its circulation depends on many factors: on the density of gas-dust environment it is moving through, on extension of the latter, on the distance to the central body, on the mass of the central body, on the mass and dimension of the celestial body, and, finally, on the speed of its movement.

The celestial mechanicians have derived the formula of the retarding force, on which the speed of approach of celestial bodies to their central body: satellites to a planet, planets to a star, stars to the centre of the Galaxy, etc. depends. If we mean not absolute, but relative deceleration of celestial bodies, i.e. the deceleration of celestial bodies with regard to each other, then this formula of relative deceleration will be as follows:

If we evaluate the radii (or diameters), masses and distances from the Sun (or orbital speeds) of the planets of the Solar System in radii (diameters), masses and distances (speeds) of Earth from the Sun, then the modern relative decelerations of the planets of the Solar System, being calculated by the above formula, would be as follows:

Mercury

Venus

Earth

Mars

Ceres

Jupiter

Saturn

Uranus

Neptune

Pluto

6,9

1,53

1,00

1,74

7,00

0,073

0,091

0,057

0,028

1,69

Looking closely at this table, one can see that the planets of the Solar System can be divided into several groups according to their relative decelerations. The first group embraces the terrestrial planets with the exception of Mercury. Their relative decelerations do not differ from one another too much being in the range from 1.00 to 1.74. The second group includes the giant planets. Their relative decelerations lie in the range from 0.028 to 0.091. Mercury, Pluto and Ceres are different from the others. The relative deceleration of Mercury and Ceres is approximately 5 times more than that of other terrestrial planets; while the relative deceleration of Pluto is about 25 times more than that of giant planets in average. Very big (about 20 times) is the difference between the relative deceleration of terrestrial planets on the one hand, and that of giant planets on the other hand.

Thus, the planets of the Solar System (like all the other celestial bodies during galactic winters), in their circulation around the Sun, are subject to deceleration by gas-dust environment, into which they sink in the course of crossing the galactic plane, spiral branches or nebulas (clouds) at the periphery of the Galaxy. At that, they come closer and closer to the Sun; the speed of this approach depends upon the value of relative deceleration. And the speed of approach determines the distance from the body to the Sun in the given moment. Hence, the distances of planets to the Sun and between the neighbouring planets (or, rather, their orbits) are in direct dependence upon the values of relative deceleration of the planets. Correspondingly, the distances of all the other celestial bodies of the Solar System, Galaxy and Metagalaxy from their central bodies, around which they circulate along their orbits, as well as the distances between these bodies (their orbits) are also dependent on the values of their relative decelerations.

However, one should remember that, first, the value of relative deceleration of a planet is not constant; it varies in the course of time with the shift of characteristics of the planet: its distance to the Sun and, accordingly, orbital speed, its mass and dimension. Second, the speed of approach of the planets and other celestial bodies of the Solar System to the central body depends not only on their relative decelerations, but also on the pace of increase of their masses, since the increase of masses of celestial bodies leads to the increase of their gravitational attraction causing additional approach to the central bodies around which they circulate.

The speed of approach of planets and other celestial bodies: asteroids, comets and meteoric bodies to the Sun and satellites – to their planets in the course of galactic winters is also influenced by a counteracting factor: acceleration (and, accordingly, withdrawal or limitation of approach of celestial bodies to the central body) under the influence of tidal friction mechanism.

If we collect the values of relative decelerations of the planets and their distances to the Sun into one table (see below), then, on the face of it, there is no interdependence between them.

PLANETS

Mercury

Venus

Earth

Mars

Jupiter

Saturn

Uranus

Neptune

Pluto

W

6,9

1,53

1,00

1,74

0,073

0,091

0,057

0,028

1,69

a

0,39

0,72

1,00

1,52

5,2

9,5

19,2

30,0

39,4

However, if we take the interplanetary distances (instead of distances to the Sun), i.e. the average distances between the orbits of neighbouring planets being equal to (an- an-1), and the ratios of distances of two neighbouring planets to the Sun being equal to (an/an-1), then we will have a distinctive dependence between the distances of planets to the Sun and the relative decelerations of the planets.

PLANETS

Venus - Mercury

Earth -Venus

Mars - Earth

Jupiter -Mars

Saturn -Jupiter

Uranus - Saturn

Neptune - Uranus

Pluto -Neptune

an – an-1

0.336

0.277

0.524

3.679

4.336

9.643

10.876

9.381

an / an-1

1.87

1.39

1.52

3.42

1.83

2.01

1.56

1.31

If we look at the second line of this table, we can see that the distances between the neighbouring planets increase gradually, so that the distance between a pair of planets more distant from the Sun is larger that that of planets that are close to it. The exceptions to this rule are the distances Mercury – Venus and Neptune – Pluto. However, as we have seen above, it is here that the border between different groups of planets concerning the values of their relative decelerations lies.

Mercury left its “fellows” from terrestrial group of planets behind: it approaches the Sun faster than the others. Its distance to Venus (0.336 AU) is more than the distance between Venus and Earth (0.277 AU). The only explanation to this is the fact that the relative deceleration of Mercury is 5 times more than those of other terrestrial planets.

Pluto is “close on the heels” of Neptune, so that sometimes cross the orbit of the latter. The distance between Pluto and Neptune (9.381 AU) is less than that between Neptune and Uranus (10.876 AU). This fact has the same explanation: Pluto has the relative deceleration that is multiply larger than those of giant planets, especially Neptune.

There are no other distinct anomalies in this line of the table. But if we turn to the third line of this table, then we could find one more anomaly in interplanetary distances. It is especially apparent, if we rearrange this line in the ascending order:

If we now remember that the anomalies in relative decelerations of the planets are in the same places where we see the anomalies in interplanetary distances, then it is clear that there is a direct interrelation between them. Indeed, there are three anomalies in interplanetary distances: first – between Mercury and Venus, second – between Mars and Jupiter, third – between Neptune and Pluto. And it is here that the sharp changes of relative deceleration take place: relative deceleration of Mercury is equal to 6.9, while those of other terrestrial planets is, in average, five times lower, so the latter fall behind Mercury in their approach to the Sun; relative deceleration of the giant planets is 20 times less than those of the terrestrial planets, and so the giant planets lag behind the latter; and the relative deceleration of Pluto is about 25 times more than those of giant planets, therefore it had come too near to them (to Neptune) and this fact could have far-reaching consequences for this planet in the future.

One could suppose (not taking the acceleration of planets under the influence of tidal mechanism into account) that, in the distant future, Mercury would leave the terrestrial planets so far behind in its motion towards the Sun, that it would fall onto the surface of the latter having been slowed down in the upper layers of its atmosphere. Pluto would come so close to Neptune that would either fall onto it, or enter the orbit around it (the latter version is less probable). It is interesting that Pluto, in case of entering the orbit around Neptune in the distant future, should, apparently, circulate around it in reverse direction. This fact prompts to think about reverse circulation of Triton around its master – Neptune. Maybe Triton once was the tenth planet of the Solar System and then entered the orbit around Neptune?

By the way, Pluto has the third prospect as well; it is connected with large inclination of its orbit (17.2°). This planet can, owing to its big (though gradually decreasing) inclination, overtake Neptune and take the place of the eighth planet. In such a case, Neptune would become the ninth one. In such a way, in the distant future, Pluto may be situated between Uranus and Neptune for some time. One may also suppose that a small planet Chiron, circling between the orbits of Saturn and Uranus, was once beyond the giant planets, but then it had overtaken them and took its modern position.

The fact that the interplanetary distances are dependent on the values of relative decelerations of planets is clearly seen from comparison of these values of giant planets. Indeed, the relative deceleration of Saturn is 1.2 times more than that of Jupiter, and so the distance between them is the least – 4.34 AU. The relative deceleration of Uranus is, on the contrary, 1.5 times less than that of Saturn, therefore the distance between them is by far more than that between Saturn and Jupiter and is equal to 9.64 AU. And the relative deceleration of Neptune is considerably less than that of Uranus. Their ratio is equal to 2.1, and, respectively, the distance between them is not large (just as we expected) – it is equal to 10.88 AU.

As to the terrestrial planets, their interplanetary distances are not in the same distinct dependence upon their modern relative decelerations. This fact testifies to another way of their origin and development. We shall dwell upon this question later.

As we have already seen, spiral branches of the Galaxy play a tremendous role in the development of celestial bodies of the Solar System; so it is necessary to elucidate the question of their origin. The fact, that many galaxies do not have spiral structure at present, prompts us to think that the spiral structure of galaxies, including our one, is a temporary phenomenon. It becomes apparent at certain stages of development of a galaxy, then – in the course of time – disappears, then – in some period of time – occurs again. Let’s ask ourselves a question, what might happen, if a huge dense gas-dust cloud from intergalactic space approaches the edge of gaseous disc of the Galaxy moving tangentially to it (ref. Fig. 6).

In the light of the aforesaid, we can answer this question in such a way. A large gas-dust cloud, having sunk into the gaseous environment of the galactic disc and being slowed down in it, would circulate around the centre of the Galaxy. Since this cloud retains the major part of its momentum, it would move around the galactic centre; and since the cloud slows down continuously in the gaseous environment of the galactic disc, then it, loosing the reserve of momentum, would circulate around the centre of the Galaxy not along a closed elliptical orbit but along a spiral approaching the galactic centre more and more.

But the cloud, in contrast to the stars, is of tremendous size and extensive shape. Its different parts are attracted to the centre of the Galaxy by different forces. Besides, the part of the cloud that is the nearest to the galactic centre would be the first to plunge into the gaseous environment of the galactic disc; and then, as the cloud approaches the centre of the Galaxy, this part would always be in more dense gaseous environment than other parts of the cloud. Therefore, the nearest part of the cloud would not only be stronger attracted to the centre of the Galaxy, but would also be decelerated more rapidly. All these factors would cause the cloud to approach the centre of the Galaxy along a spiral, differentially. The nearest part of the cloud would approach the centre of the Galaxy at higher speed, while the distant part – at lower speed. And when the former nears the galactic centre already, the latter is only at the periphery.

The spiral structure of Galaxy, having appeared in such a way, would later on be supported by other, smaller clouds coming to the sphere of influence of the Galaxy from the intergalactic space. Those of them being in the galactic plane in front of a spiral branch would be decelerated even more, because they have lower density and the spiral branch, having overtaken them, would annex them. And those of them moving around the centre of the Galaxy
behind a spiral branch would be “in the shadow” of the latter, where the density of gaseous environment is multiply lower than in the gaseous disc of the Galaxy on average, since a spiral branch scoops the diffuse matter during its motion around the galactic centre. As a result, these clouds would be decelerated not so much as the spiral branch; they would overtake and join it, increasing its mass and density.

Nevertheless, the role of the main suppliers of gas and dust to the spiral branches is played by huge gas-dust clouds that periodically come to galaxies from intergalactic space, generate the spiral branches and then feed them. However, the substance of one or another gas-dust cloud exhausts sooner or later; and the spiral branch being fed from this cloud begins to be reduced both by length, width (diameter) and density. And since the spiral branch now gets less diffuse matter than it returns to the stars passing through, it begins to diffuse after the disappearance of the cloud and soon disappears itself, having given the remainder of gas and dust to the stars. But, since new clouds will approach the Galaxy in the course of time, they will generate (revive) spiral branches; the latter will occur and, having existed for some time, will diffuse and disappear again.
Spiral branches are similar to the earthly rivers originating in the bogs (gas-dust cloud), that feed them, and flowing to lakes or seas (the centre of the Galaxy). If the bog dries out in droughty weather, then the river being fed by this bog would dry up as well
.